Month: October 2014

Last week, I posted about my encounter with the impressively aggressive and carnivorous mice (Onychomys), which ended in me leaving a number of motion-sensing infrared video cameras at a long term ecology site near Portal, Arizona. I’m happy to report I have some footage of these mighty hunters. (The team from the Ernest lab had trapped a number of Onychomys they ID’d as species torridus on the plots where I placed these cameras just nights before, so my educated guess is that these videos are of O. torridus, but if any mammologists can distinguish the species more definitively from these videos, I’d love to hear about it.)

I baited the cameras with mixed birdseed, so I had lots and lots of videos of granivorous (seed eating) kangaroo rats and pocket mice to view, like these:

But about an hour after the pocket mouse (above) was last seen walking through that path in the grass, look who followed:

The southern grasshopper mouse (I think)! Also known as the scorpion mouse, because it takes down all kinds of dangerous and venomous arthropods, as well as animals nearly its own size. And ten minutes later it (or another one, can’t tell for sure) came back through again, definitely looking like it was tracking something:

Wait, why did I bait the cameras with birdseed when I was seeking carnivorous animals? Although grasshopper mice are carnivorous, they are commonly captured in live traps baited with seeds and oats. I had wondered whether they were at all interested in the seeds, or whether they smelled animals previously trapped in that box and were looking for prey – or whether they were just curious and exploring. (Plus, I was secretly hoping I would capture a grasshopper mouse killing the pocket mouse that was eating the bait. No luck.)

One video seems to answer my question: even if these mice can be completely carnivorous, some are open to trying new food:

I hear a certain large foreign TV network is working on a documentary about these animals. To get high-quality video images, they have to capture a number of animals, then stage encounters by placing a grasshopper mouse and, say, a tarantula in a sandbox together. I like to think that although my footage is less polished, it provides a complementary view of their lives by peering at what happens on a daily basis out in the wider world, where anything could happen.